Abstract: A concrete crusher has a crushing surface 1a on a stationary lower jaw 1 and it is formed so that its axial cross-section is V-shaped. A main crushing blade 5 is installed on a crushing surface 2a of a movable upper jaw 2 pivoted to the lower jaw and is opposite the lowermost portion of stationary crushing surface 1a. Supporting crushing blades 6 are installed on the upper jaw at opposite sides of the main crushing blade 5 and have shorter blade heights than main crushing blade 5.

Abstract: Breaking equipment comprising a mounting bracket that is attached to an arm of a power shovel for vertical pivotal movement, a holder frame mounted on the mounting bracket for swivel movement, a hydraulic motor attached to the mounting bracket for rotatably and reversibly driving the holder frame or a swivel break mechanism which is used in place of the hydraulic motor for restricting swivel movement of the holder frame, a pair of pivot arms of a symmetrically L-shaped configuration attached at their mid points to the holder frame by means of pivot axes, the pivot axes being separated apart a predetermined distance H from one another so as to satisfy the equations; a=<b and H=<2h, wherein, a is a distance from the pivot point to the forward end of each of the pivot arms, b is a distances from the pivot point to the rearward end of each of the pivot arms, and h is a distance from the blade edge vertically to the line connecting the pivot point and the forward point of the application, a hydraulic cylinde